Free alarm clock version contains in-app ads and has some limitations.

What's more in PRO version:- no ads- annual/Birthday/Anniversary alarm- cyclic alarm repeat up to 90 days- cyclic alarm can be repeated every x-th month- sunrise and sunset alarms (with dawn and dusk support)- shake to snooze- snooze count up to 100- full alarm profiles support

Permissions:READ_PHONE_STATE - to detect incoming phone call and snooze alarm.RECEIVE_BOOT_COMPLETED - to set up alarms after phone start.ACCESS_NETWORK_STATE, INTERNET - ads, checking for new app version, Google Analytics, Firebase Analytics, Google Drive.WRITE_EXTERNAL_STORAGE/READ_EXTERNAL_STORAGE - backup/restore settings, play ringtones located on external memory.WAKE_LOCK - to wake device and show alert window on time.DISABLE_KEYGUARD - disable keyguard (lock screen) when alarm starts.VIBRATE - vibrate during alarm.ACCESS_COARSE_LOCATION - optionally used on Andorid 6+ devices to calculate sunrise/sunset time for current location. User has to grant application that permission. Otherwise applciaiton does not have access to GPS data.